Wilbur de Kruijf at Recipharm highlights the importance of preparing for the next pandemic by developing more effective ways to deliver vaccines against emerging infectious diseases and poses the question: do vaccines delivered via a soft mist nasal spray device hold the key to an enhanced immunization response?
The COVID-19 pandemic was marked by the number of successes achieved by the pharmaceutical industry, particularly the creation of vaccines in record time thanks to cross-industry collaboration. However, looking back, it’s clear that there are still lessons to be learnt about improving our response to the next viral threat.
In the ongoing search for better solutions, the industry can continue to depend on the support of the contract development and manufacturing organisations (CDMOs) that played an important role in developing many of the currently available vaccines. One vitally important hurdle to overcome, though, is the need to improve the way we deliver vaccines; solutions to provide better efficacy and even more convenience during administration are essential.
Recent studies suggest that vaccine delivery via the mucosal membrane provides a better, longer-lasting effect than traditional injections, even at a lower dose.1
Administering vaccines at the predominant sites of pathogen infection can trigger a stronger immune response by encouraging adaptive immunity at mucosal sites — involving secretory antibody responses and tissue-resident T cells — which could prevent infection entirely.
Developing nasal vaccines might also offer benefits compared with injectables owing to their non-invasive, more targeted means of delivery. As a result, nasal vaccines could offer reduced side-effects, a faster response and a better patient experience.
To establish a nasal vaccine, it must first go through a complete clinical programme; after that, a modified vaccine based on the same device and on the same formulation and excipients, has the potential to be approved following an abbreviated regulatory filing.
For recipients themselves, the nasal delivery of a vaccine could remove one of the major obstacles to vaccine uptake: needle phobia. Data regarding the prevalence of this condition vary, but the figures range from 3.5–20% of the US population.2 By comparison, vaccination via nasal delivery would negate any hesitancy caused by needles among patients.
Despite nasal delivery offering several advantages compared with other delivery routes, there are still challenges that need to be addressed when delivering biologics such as vaccines. One study found that lipid nanoparticles, necessary for the delivery of mRNA vaccine formulations, were damaged when aerosolised into a spray.3
Finally, dose volume and the area of the nasal cavity to be targeted is critical for the efficacy of a vaccine and other biologics. Standard nasal sprays feature swirl nozzles with a typical spray cone angle of 60–90°, which limits the ability of the formulation to penetrate the nasal cavity and negatively impacts dose uniformity during delivery.
However, a new generation of soft mist nasal sprays offers the ability to navigate these challenges. Soft mist devices are liquid sprays that are capable of producing a slow-moving cloud of aerosolised drug formulation that penetrates the nasal cavity.
A crucial benefit of these devices is their ability to dispense a sensitive vaccine or biologic product while minimising the degradation of lipid nanoparticles within the formulation. Soft mist nasal sprays feature spray nozzles that have the ability to produce a narrower spray cone.
This reduced spray cone angle allows the formulation to better penetrate the nasal cavity and improve dose uniformity. One such example allows the fine-tuning of the spray cone angle from 0° to 30°. This delivers a higher dose in the upper turbinates and olfactory centres of the nasal cavity, ensuring an effective and even dose that’s capable of optimising the efficacy of a nasal vaccine.1,4
By making nasal vaccine delivery possible, soft mist nasal sprays can help to make future vaccination programmes more convenient and efficient for healthcare providers, offer greater patient experience and have the potential for better therapeutic effect. A new pandemic will arrive; the question is when, not if. As such, the importance of an effective alternative approach to injectable vaccines prior to its emergence is crucial.